Star Wrath

Every swing drops stars out of the sky well above your head, angled toward wherever your cursor sits. They fall through terrain on the way down and only start colliding with blocks once they reach roughly the height you were pointing at, so you can hit things through a ceiling as long as the cursor is on them. They also spawn from a spread of positions behind and above you, which is why the pattern feels loose rather than aimed.

In a closed hallway most of the stars land somewhere other than the fight and you are effectively swinging a plain sword. Give it open ground and holding the attack puts a constant fall of light over one patch of the screen, which is why it flattens invasion waves and works so well from a platform arena. Point at a top corner of the screen and the stars come in almost sideways, which travels absurdly far and is entertaining more than it is useful.

Even once you have something better in hand, it is a required component of the Zenith. Selling it or feeding it to shimmer means going back to the Moon Lord for another. Treat it as the grown-up Starfury, since it plays exactly the same way with far more weight behind it.